1. Field of the Invention
This invention relates to a calibration assisting method, device and system, and more particularly to a calibration assisting method, device and system for assisting the calibration of a weight meter for measuring the loaded weight of a vehicle produced from a load sensor. The load data varies according to a distortion of an axle, which is generated when the load applied to the vehicle is conducted to the axle.
2. Description of the Related Art
The measurement of the weight loaded on a vehicle is carried out, for a large vehicle such as a truck, in order to prevent a traffic accident such as turnover on the side of the vehicle due to overloading and promotion of vehicle deterioration. Conventionally, measurement of loaded weight of the vehicle was carried out in such a manner that the vehicle is placed on a platform scale. This manner requires large-scale facilities and a large installing space. Therefore, the number of the platform scales, which can be set, is limited and hence the measurement cannot be carried out for a large number of vehicles. In addition, the production cost is also increased.
In order to obviate these inconveniences, in recent years, a weight meter has been proposed in which it is mounted on the vehicle itself to measure the loaded weight. In a conventional weight sensor mounted on the vehicle, sensors for weight measurement, e.g. strain gage sensors are attached to both left and right ends of each of both front and rear axles. The loaded weight is measured on the basis of the sum of the outputs of the respective sensors, which are proportional to the loads applied to the front/rear and left/right tires.
In the weight meter, in order to maintain the measurement accuracy, the relationship between the outputs from the sensors and an actual weight of the matter to be measured is investigated, and on the basis of the investigation result, a sensor signal is calibrated. There is the following known calibrating method.
For example, with a weight loaded on a stand installed on the upper portion of a container, calibration is carried out. In this case, a specific structure is required to fix the stand to the container. In addition, since excessive load is applied from the upper portion of the container, the container may break. The labor of placing a large number of weight members placed at a height of 2 meter or higher is enormous and entails danger.
The method for calibrating the weight meter safely and easily is disclosed in JP-A-2001-228015. In accordance with this method, the weight meter can be calibrated safely and easily in such a manner that a plurality of spring members are hung from the container for accommodating a matter to be conveyed, a weight member having a prescribed weight is placed on a stand supported by the spring member and the relationship between the output of the load cell sandwiched between the container and the body frame of the vehicle and the weight of the weight member is examined.
However, since the above calibration method is carried out using the weight member, time and labor are required to load/unload the weight member so that the weight meter cannot be calibrated for a short time. A structure must be provided for supporting the above stand with respect to the container, vehicle, etc.